Load User Defaults list asynchronously to improve performance (#22535)

Author: Artyom Vlasov

WordPress/Classes/ViewRelated/Me/App Settings/Boolean User Defaults/BooleanUserDefaultsDebugViewModel.swift

@@ -1,54 +1,75 @@
 import SwiftUI
+import Combine
 
 final class BooleanUserDefaultsDebugViewModel: ObservableObject {
+
     private let persistentRepository: UserPersistentRepository
-    private let coreDataStack: CoreDataStack
+    private let coreDataStack: CoreDataStackSwift
+    private var allUserDefaultsSections = Sections()
+    private var cancellables = Set<AnyCancellable>()
 
-    private var allUserDefaultsSections = Sections() {
-        didSet {
-            self.reloadSections()
-        }
-    }
+    // MARK: - State
 
     @Published var searchQuery: String = "" {
         didSet {
-            self.reloadSections()
+            Task { @MainActor in
+                self.reloadSections()
+            }
         }
     }
 
-    @Published var userDefaultsSections: Sections = []
+    @MainActor @Published private(set) var userDefaultsSections: Sections = []
+
+    // MARK: - Init
 
-    init(coreDataStack: CoreDataStack = ContextManager.shared,
+    init(coreDataStack: CoreDataStackSwift = ContextManager.shared,
          persistentRepository: UserPersistentRepository = UserPersistentStoreFactory.instance()) {
         self.coreDataStack = coreDataStack
         self.persistentRepository = persistentRepository
     }
 
+    // MARK: - Load
+
     func load() {
+        Task {
+            await self.load()
+        }
+    }
+
+    func load() async {
         let allUserDefaults = persistentRepository.dictionaryRepresentation()
         var loadedUserDefaultsSections = Sections()
         var otherSection = [Row]()
 
         for (key, value) in allUserDefaults {
             if let groupedUserDefaults = value as? [String: Bool], !isFeatureFlagsSection(key) {
+                let rows = await processGroupedUserDefaults(groupedUserDefaults)
                 let section = Section(
                     key: key,
-                    rows: processGroupedUserDefaults(groupedUserDefaults)
+                    rows: rows
                 )
                 loadedUserDefaultsSections.append(section)
             } else if let booleanUserDefault = value as? Bool, !isGutenbergUserDefault(key) {
                 otherSection.append(.init(key: key, title: key, value: booleanUserDefault))
             }
         }
+
         if !otherSection.isEmpty {
             let rows = otherSection.sorted { $0.title < $1.title }
             let section = Section(key: Strings.otherBooleanUserDefaultsSectionID, rows: rows)
             loadedUserDefaultsSections.append(section)
         }
-        allUserDefaultsSections = loadedUserDefaultsSections
+
+        self.allUserDefaultsSections = loadedUserDefaultsSections
+
+        await MainActor.run {
+            self.reloadSections()
+        }
     }
 
-    private func reloadSections() {
+    // MARK: - Helpers
+
+    @MainActor private func reloadSections() {
         self.userDefaultsSections = filterUserDefaults(by: searchQuery)
     }
 
@@ -73,22 +94,28 @@ final class BooleanUserDefaultsDebugViewModel: ObservableObject {
         return filteredSections
     }
 
-    private func processGroupedUserDefaults(_ userDefaults: [String: Bool]) -> [Row] {
-        var rows = userDefaults.reduce(into: [Row]()) { result, keyValue in
-            let (key, value) = keyValue
-            result.append(processSingleUserDefault(key: key, value: value))
+    private func processGroupedUserDefaults(_ userDefaults: [String: Bool]) async -> [Row] {
+        let rows = try? await self.coreDataStack.performAndSave { [weak self] context -> [Row] in
+            guard let self else {
+                return []
+            }
+            return userDefaults
+                .reduce(into: [Row]()) { result, keyValue in
+                    let (key, value) = keyValue
+                    let row = self.processSingleUserDefault(key: key, value: value, in: context)
+                    result.append(row)
+                }.sorted { $0.title < $1.title }
         }
-        rows = rows.sorted { $0.title < $1.title }
-        return rows
+        return rows ?? []
     }
 
-    private func processSingleUserDefault(key: String, value: Bool) -> Row {
-        let title = findBlog(byID: key)?.url ?? key
+    private func processSingleUserDefault(key: String, value: Bool, in context: NSManagedObjectContext) -> Row {
+        let title = findBlog(byID: key, in: context)?.url ?? key
         return Row(key: key, title: title, value: value)
     }
 
-    private func findBlog(byID id: String) -> Blog? {
-        return try? Blog.lookup(withID: Int(id) ?? 0, in: coreDataStack.mainContext)
+    private func findBlog(byID id: String, in context: NSManagedObjectContext) -> Blog? {
+        return try? Blog.lookup(withID: Int(id) ?? 0, in: context)
     }
 
     func updateUserDefault(_ newValue: Bool, section: Section, row: Row) {

WordPress/WordPressTest/Me/App Settings/Boolean User Defaults/BooleanUserDefaultsDebugViewModelTests.swift

@@ -1,16 +1,19 @@
 import XCTest
+import Combine
 @testable import WordPress
 
 private typealias Section = BooleanUserDefaultsDebugViewModel.Section
 private typealias Row = BooleanUserDefaultsDebugViewModel.Row
 
-class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
+@MainActor final class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
 
     var viewModel: BooleanUserDefaultsDebugViewModel!
     var mockPersistentRepository: InMemoryUserDefaults!
+    var cancellables: Set<AnyCancellable>!
 
     override func setUp() {
         super.setUp()
+        cancellables = .init()
         mockPersistentRepository = InMemoryUserDefaults()
         viewModel = BooleanUserDefaultsDebugViewModel(coreDataStack: contextManager,
                                                       persistentRepository: mockPersistentRepository)
@@ -22,12 +25,12 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         super.tearDown()
     }
 
-    func testLoadUserDefaults_WithOtherSection() {
+    func testLoadUserDefaults_WithOtherSection() async {
         // Given
         mockPersistentRepository.set(true, forKey: "entry1")
 
         // When
-        viewModel.load()
+        await viewModel.load()
 
         // Then
         XCTAssertTrue(viewModel.userDefaultsSections.count == 1)
@@ -38,12 +41,12 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         XCTAssertTrue(viewModel.userDefaultsSections.first?.rows.first?.value == true)
     }
 
-    func testLoadUserDefaults_WithoutOtherSection() {
+    func testLoadUserDefaults_WithoutOtherSection() async {
         // Given
         mockPersistentRepository.set(["entry1": true], forKey: "section1")
 
         // When
-        viewModel.load()
+        await viewModel.load()
 
         // Then
         XCTAssertTrue(viewModel.userDefaultsSections.count == 1)
@@ -54,10 +57,10 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         XCTAssertTrue(viewModel.userDefaultsSections.first?.rows.first?.value == true)
     }
 
-    func testUserDefaultsSections_MatchingQuery() {
+    func testUserDefaultsSections_MatchingQuery() async {
         // Given
         mockPersistentRepository.set(["match": true], forKey: "section1")
-        viewModel.load()
+        await viewModel.load()
 
         // When
         viewModel.searchQuery = "mat"
@@ -71,25 +74,33 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         XCTAssertTrue(viewModel.userDefaultsSections.first?.rows.first?.value == true)
     }
 
-    func testUserDefaultsSections_NotMatchingQuery() {
+    func testUserDefaultsSections_NotMatchingQuery() async {
         // Given
+        let expectation = expectation(description: "List should be empty when no matching entries")
         mockPersistentRepository.set(["entry1": true], forKey: "section1")
-        viewModel.load()
+        await viewModel.load()
 
         // When
+        viewModel.$userDefaultsSections
+            .dropFirst()
+            .sink { sections in
+                XCTAssertTrue(sections.isEmpty)
+                expectation.fulfill()
+            }
+            .store(in: &cancellables)
         viewModel.searchQuery = "noMatch"
 
         // Then
-        XCTAssertTrue(viewModel.userDefaultsSections.isEmpty)
+        await fulfillment(of: [expectation], timeout: 1)
     }
 
-    func testUserDefaultsSections_WithFilteredOutNonBooleanEntries() {
+    func testUserDefaultsSections_WithFilteredOutNonBooleanEntries() async {
         // Given
         mockPersistentRepository.set(["entry1": "NotBoolean"], forKey: "section1")
         mockPersistentRepository.set(["entry2": false], forKey: "section1")
 
         // When
-        viewModel.load()
+        await viewModel.load()
 
         // Then
         XCTAssertTrue(viewModel.userDefaultsSections.count == 1)
@@ -100,32 +111,32 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         XCTAssertTrue(viewModel.userDefaultsSections.first?.rows.first?.value == false)
     }
 
-    func testUserDefaultsSections_WithFilteredOutGutenbergItems() {
+    func testUserDefaultsSections_WithFilteredOutGutenbergItems() async {
         // Given
         mockPersistentRepository.set(true, forKey: "com.wordpress.gutenberg-entry")
 
         // When
-        viewModel.load()
+        await viewModel.load()
 
         // Then
         XCTAssertTrue(viewModel.userDefaultsSections.isEmpty)
     }
 
-    func testUserDefaultsSections_WithFilteredOutFeatureFlagSection() {
+    func testUserDefaultsSections_WithFilteredOutFeatureFlagSection() async {
         // Given
         mockPersistentRepository.set(["entry1": true], forKey: "FeatureFlagStoreCache")
 
         // When
-        viewModel.load()
+        await viewModel.load()
 
         // Then
         XCTAssertTrue(viewModel.userDefaultsSections.isEmpty)
     }
 
-    func testUpdateUserDefault_OtherSection() {
+    func testUpdateUserDefault_OtherSection() async {
         // Given
         mockPersistentRepository.set(true, forKey: "entry1")
-        viewModel.load()
+        await viewModel.load()
 
         // When
         let section = viewModel.userDefaultsSections[0]
@@ -141,10 +152,10 @@ class BooleanUserDefaultsDebugViewModelTests: CoreDataTestCase {
         XCTAssertTrue(viewModel.userDefaultsSections.first?.rows.first?.value == false)
     }
 
-    func testUpdateUserDefault_GivenSection() {
+    func testUpdateUserDefault_GivenSection() async {
         // Given
         mockPersistentRepository.set(["entry1": true], forKey: "section1")
-        viewModel.load()
+        await viewModel.load()
 
         // When
         let section = viewModel.userDefaultsSections[0]